Call interlocking type information providing service in which in conjunction with a telephone call, i.e., voice communication performed by users by using telephones such as fixed-line phones and mobile phones, users performing a telephone call give and receive information such as still images and moving images each other by using information display terminals such as PCs (Personal Computers) and potable terminals has been studied.
For example, Patent literature 1 discloses a service providing system in which: every time a telephone call is established, call information such as a telephone number is notified from an in-house control apparatus to an information providing server; and the information providing server performs an information providing service start process based on that call information. The information providing server identifies two information display terminals that have been associated with the telephones in advance, based on the notified call information, memorizes the pair of information display terminals, and performs a process for waiting for a connection from the information display terminals.
Further, Patent literature 2 discloses a data exchange system for realizing cooperation between data communication for sharing moving images and still images and voice communication. In this data exchange system, a home gateway performs voice communication and data communication by using two types of communication networks, i.e., a closed area communication network such as the NGN (Next Generation Network) and a wide area communication network such as the Internet. By adopting such a configuration that the home gateway exchanges destination information such as an IP (Internet Protocol) address through one communication network, the need for managing destination information for a plurality of communication networks for each person or device to be communicated is eliminated. Therefore, it is possible to seamlessly use communication in a plurality of communication networks.